Method of casting projectiles



(No Model.) 3 Sheets-Sheet 1.

J. A. POTTER. METHOD OF CASTING PROJEGTILES.

No. 534,665. Patented Feb. 26-, I895.

WITNESSES INVENTOR WWW? I aw. wow:

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JOHN A. POTTER, OF MUNHALL, PENNSYLVANIA.

METHOD OF CASTING P ROJECTILES.

SPECIFICATION forming part of Letters Patent No. 534,665, dated February 26, 1895.

Application filed February 27,1893. Serial No 463.902. iNomodel.)

T0 aZZ whom it may concern:

Beit known that I, JOHN A. POTTER, of Munhall, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Casting Projectiles and other Articles, of which the following is a full, clear, and exact description.

My invention relates to an improvement in the art of casting projectiles, other finished articles, and also ingots intended to be subsequently worked; and it consists in applying pressure to the molten steel in the mold in the manner hereinafter described.

I will now describe my invention so that others skilled in the art may employ the same, reference being had to the accompanying drawings, forming part of this specification, in which- Figure 1 is a side elevation, partly in section, of apparatus which maybe employed in carrying my invention into efiect. Fig. 2 is an end elevation, partly in section. Fig. 3 is an enlarged sectional view of the mold. Figs. 4: and 5 are detached views of the cores. Fig. 6 is a vertical sectional view of the projeaiLle/ and Fig. 7 is an end elevation, partly in section, showing a modification.

Like symbols of reference indicate like parts in each figure.

In the drawings, 2 represents the ladle containing the molten steel as it is brought from the furnace, which ladle is supported by a suitable crane over the molds These molds are provided with wheels 4:,Tibunted on trunnions extending from the sides of the molds, which wheels rest on the track 5. Inside of the molds at the-bottom of the cavities are the plugs or shoes 6. Situate on the line of the track 5 is a hydraulic press having a plunger-head 7 and a plunger 8, fitting in the hydraulic cylinder 9, having water connections for imparting a downward movement to the plunger 8. At the sides of the cylinder 9 are the lifting hydraulic cylinders 20, having plungers 21 connected with the plunger-head 7, arranged to lift the plunger-head after it has completed its downward stroke. These cylinders are provided with suitable hydraulic connections.

Situate below the track 5, on a vertical line with the plunger 8, is a hydraulic cylinder 10,

having a plunger 11 adapted to rise vertically the cavity of the mold, the mold is driven' along the track 5 until it is brought directly under the pin 12 ot the plunger-head 7. Prior to the casting or at the same time therewith, a core cylinder It has been placed over the pin 12. This core cylinder is formed of sheet steel, closed at the bottom, and is corrugated, as is shown in Fig. 4, and is adapted to fit loosely on the pin 12, yet so as to engage sufficiently therewith to retain its position thereon, which engagement may be formed by placing san'd within the core cylinder, which also serves to protect the pin 12 from the action of the heat when the core cylinder and pin are caused to enter the molten metal in the mold. When the mold containing the molten metal is brought below the'pin 12, a steel ring 15 of about the circumference of the cavityof the mold and having a central opening 16 of sufficient size to permit the passage of the cylinder 14, is placed on top of the molten metal in the mold. The plunger 11 is then caused to ascend and lift the mold from off the track and the plunger 8 is caused to descend, which carries the core cylinder 14 through the opening in the ring 15 into the center of the molten metal, and'brings the head 13 down on the ring 15. This serves to compress the molten metal in the mold not only from the center by the entrance of the core 14, but from the top by the head 13 bearing down on the ring 15. As soon as the metal has thoroughly congealed under the pressure, the plunger 8 is raised, withdrawing the pin 12 from the mold and leaving the core 14 and ring 15 united with the metal in the mold, forming part of the projectile or other article. The purpose of the corrugations in the core cylinder is to allow of the contraction of the cylinder. under the force of the contraction of the surrounding metal in cooling, and, instead of corrugating thel cylinder, the same end may be attained by forming the cylinder with a turned-in sliding joint as is shown in Fig. 5; but I do not desire to limit myself to any particular form of corrugation or sliding joint, as the position and shape of the corrugations and joints may be varied by those skilled in the art. The pin 12 having been withdrawn from the mold, the mold is moved along the track 5 and tilted on its trunnions so as to discharge the projectile or other article therefrom, and a second mold is brought under the plunger 8 and over the plunger 11 and the same operation is repeated.

Instead of using both an ascending plunger to lift the mold and a'descending plunger to carry the core into the mold, the head 7 may be fixed and stationary, and the plunger 11 may be so arranged as to carry the mold up against the head and around the core on the pin 12. V

Projectiles or shells formed in the manner described have a central cavity when finished; which is the space occupied by the pin 12, and the sand placed about the pin, and other hollow articles may be formed in a like manner. When, however, it is. desired to form solid projectiles, ingots or other solid articles, the pin 12 and core 14: are omitted and the head 13 is caused to bear directly on a plate or disk instead of the ring 15, which disk is placed on top of the metal in the mold and on being subjected to pressure in the manner described unites with the molten steel, the molten steel being at the same time compressed in the mold.

When it is desired to form articles having a soft or hard center and a hard or soft exterior surface, a solid core or plate of soft or hard metal is used in place of the core-cylinder 14, the plate or core being detachably attached to the head 13 and serving to press the molten metal from the center as well as to form the soft or hard center of the ingot or other article. 1

In order to carry out the foregoing method successfully, care must be taken that the compression of the molten metal commences before the metal starts to congeal, and that it "be maintained until the metal is thoroughly congealed.

Where articles having collars or projections are to be formed, a mold divided in two parts may be employed, hydraulic or other devices being used to retain the parts of the mold in position during the pressing operation as in Fig. 7, wherein I show hydraulic cylinders 16 arranged to press the halves 3 of the mold together when in place below the plunger 8.

The advantages of my improved method are that the pressure is effectively and evenly applied to all parts of the article and the metal is rendered dense and homogeneous through.- out, and all piping or irregularity of density in the center of the article is prevented, the pressure being exerted from that point, and a cast steel article having the properties of forged steel is produced.

I am aware that it is not new to compress partially congealed molten metal in the mold in the manufacture of projectiles and other articles by inserting a metal tool or core and withdrawing the core or tool, and I do not de sire to claim the same, as it would be impossible by this method to allow the tool or removable core to remain in the molten metal during the time required for the metal to congeal and then remove the tool without destroying the tool or ingot.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, is

1. The herein-described method of casting articles of steel, consisting in subjecting the uncongealed metal to pressure from its center by forcing a metal core into the molten steel in the mold, at the same time subjecting the molten metal to pressure on its outer surface, and allowing the metal core to unite with the molten steel; substantially as described.

2. The herein-described method of casting articles of steel, consisting in pressing a hollow core into the uncongealed molten metal, subjecting the metal to pressure on its outer surface, and allowing the core to unite with the molten steel; substantially as described.

3. The herein-described method of casting articles of steel, consistingin pressing a metal disk or plate against the surface of the un. congealed metal in the mold and allowing the disk to unite with the molten metal; substantially as described.

4. The combination of a press having a core pin a hollow compressible core, and a mold substantially as specified.

In testimony whereof I have hereunto set my hand.

- JOHN A. POTTER.

WVitnesses:

R. H. WHITTLEsEY, H. M. ConwIN. 

